Steam heating system and method of supplying steam to the radiators thereof



Dec. 21, 1937. R1. RAYMOND -STEAM HEATING SYSTEM AND METHOD OF SUPPLYINGSTEAM TO THE 'RADIATORS THEREOF 2 Sheets-Sheet 1 Filed March 22, 1934Dec.21, 1937. F. l. RAYMOND 2,103,178 STEAM HEATING SYSTEM AND METHOD OFSUPPLY'I-NG STEAM TO THE RADIATORS THEREOF '2 Sheets-Sheet 2 Filed March22, 1934 m W.) a a V/ w m 1 w gwmmg Patented Dec. 21, 1937 PATENT OFFICESTEAM HEATING SYSTEM AND METHOD OF SUPPLYING STEAM TO THE RADIATORSTHEREOF Fred 1. Raymond, River'Forest, Ill.

Application March 22, 1934, Serial No. 716,914

6 Claims.

My invention relates primarily to steam heating systems, whether of theso-called steam, vapor, or vacuum type, comprising radiators in theseveral rooms of a building, a system of supply pip- 5 ing forconducting steam to each of the radiators from a central point, and aseparate system of return piping for collecting the condensate from theseveral radiators and conductingit back to a desired point, my presentinvention being a continuation, in part, of my application for UnitedStates Letters Patent Serial No. 272,330, filed April 23, 1928.

One of my objects is to provide for the distributing of proportionatequantities of steam to the various radiatorsof a steam heating system ofthe so-called orificed type, at reduced capacities as well as at maximumcapacity. While this object has been the object of previous systems ofthe so-called orificed type there are certain practical limitations inthe apparatus that have hitherto been used which limitations haveprevented the prior systems from accomplishing: the full measure ofperformance that I am able tosecure by my invention.

Another object is to provide for the distributing of the sameproportionate quantities of steam to the radiators at the top of a tallbuilding as to the radiators at the bottom of the building at allcapacities, a result which has not been hitherto attempted so far as Ican ascertain. Theneed for it arises out of the fact that the pressuredifferential tending to force steam into the radiators at the top of thebuilding is greater than the differential at the bottom of thebuilding'due to the buoyancy of the steam in the system of supply pipingas compared with the heavier airin the system of return piping. Thisdifference in difierential is most pronounced in tall buildings becausethe difierence in weight between the column of air in the return pipingand the column of steam in the supply piping is directly proportional tothe height of the column. This difference in differential between thatat the top and that at the bottom of the building may be called thealtitude head! It is a serious handicap in the operation of previoussystems because it remains practically constant at all capacities andasthe differential in pressure is reduced for opera tion at lowercapacities, the. altitude headbecomes an increasing proportion of the'totaldif ferential.

As the differential in pressure is reduced, the point is finally reachedwhere the difierential at the bottom of the building will be zero whilethe differential'at the top of the building will still'be equal to thealtitude head. 'The seriousness" of this defect will be realized byconsidering the case of a building in which the top radiatoris 217- feetr higher than the bottom. Based on thedensity of saturated steam at 212F. and. that of'dry air at 100 F. the altitude head would be equal to.1" of mercury. If the radiators of a system in such a building wereequipped with orifices at the entrances to the radiators so sized thatthe radiators at the top and bottom'would each receive 100% of thedesired quantities of steam when the diferential at thebottom'orifice'was 1.0" of mercury, then when the differential wasreduced'by. throttling the supply of steam to the system to a pointwhere the difierential at the bottom was zero, here would still be adifierential of .1" at the top radiator. This differential of .1" at thetop orifice would produceapproximately 30% as much flow through thetoprorifice as with the design differential of 1.1" for the top orificeforits rated capacity. Thus in such a system in a building 217 feethigh, it would be necessary to supply 30% of the rated capacity of steamto the top radiator before any steam could bedelivered to the bottomradiator.

Some of the manufacturers of previous socalled orificed systems haverealized this inherent limitation of altitude head, and have sought tominimize it by using a design differential much higher than 1'of mercurysuch as 2" or 4" and even 8" and. 10". By doing so they have been ableto keep the altitude head a much smaller proportionof the total head.However, atthese higher diiferentials, the velocity of the steam throughthe orifices is so great that it causes a hissing sound which is audiblein the rooms and objectionable for that reason. 7

Another limitation of previous orificed SYS". terms, which limitation Iovercome by my invenftion, arises out of the fact that the flow of steamthrough an orifice is substantially proportional to the square root ofthe pressure differential 1, 19,7 5 the orifice. Thus the quantities ofsteam which will flow through an orifice designed to give 100% ofcapacity at 1" diiferential are as follows:

Pressure Percent differential oi flow l. 0 Hg 100 From the above tableit is evident that the differentials required at low capacities are veryminute quantities. Not only is extremely accurate and sensitive pressurecontrolling apparatus required, but it also becomes extremely diificultto produce these same pressure diiferentials or the same relativepressure differential in all parts of the system. While it istheoretically possible to place additional orifice plates in the branchsteam lines of such a system and thereby correct for drop indifferential due to difierent sizes and lengths of the supply pipes, itbecomes an extremely delicate and tedious operation in actual practice.Moreover, even after all corrections have been made for resistancetoflow in the supply piping, the defect of unequal fiow due to altitudehead still remains.

The first referred to object of my invention can be best understood bycomparing the following table of pressure difierentials at which I mightchoose to operate my system with the table of pressures given above.

Percent of flow Pressure difierential By comparison it will be notedthat for 20% capacity with my system, I would require a differential of.2" Hg as opposed to .04 Hg under previous systems. The differentialwould be five times as great with my system as in previous systems at20% of capacity provided both systems were designed to give 100% flow atthe same differential. Similarly, my system would employ ten times asmuch differential at 10% of capacity as previous systems. Because ofthis greater differential at reduced capacities, the pressurecontrolling apparatus would not need to be nearly so sensitive as withprevious: systems. Also the efiect of piping resistance would be of muchless importance. Also there would be considerable advantage from thestandpoint of instructing an operator to have a system in which twice asmuch pressure differential would give twice as much flow. It would besimpler too to build controlling apparatus which operated to producepressures directly proportional to required capacities than it is tobuild controls to operate on a square root basis of increment.

My approach to the accomplishment of the second object of my inventioncan be best understood by reference to the example previously given of.1" Hg altitude in a building 217' high. In that example I pointed outthat the .1 differential due to altitude head would produceapproximately 30% flow through the top orifice while the flow at thebottom was zero. This defeet can be overcome if an orifice wereinstalled in the upper radiator which would give 0% of flow at .1"pressure differential. Both the limitations of square root fiow andaltitude head could be overcome if orifices were to be installed in thetop and bottom radiators which would give the following performance:

Pressure Percent Pressure Percent difierential of flow at differentialof [low at bottom bottom at top at top 1.0 Hg 100 1 1" Hg 100 .9 90 8 809 80 7" 70 8 70 6 60 7" 60 .5 50 .6" 50 4 4O .5 i0 3 30 4" 30 2 20 3 201" 1O 2 l0 .0 0 l 0 Having outlined my approach to a solution of theproblem, it will now be simple to understand the means I have used.

I have obtained the first object of my invention by designing an orificewhich automatically decreases in size by the proper amount as thepressure differential decreases. Thus I am able to decrease the flowthrough the orifice not only due to the reduced velocity of steamthrough the orifice due to reduction indifferential but also due to thereduction in size of the orifice.

I have attained the second object of my inven tion by designing anorifice which can be adjusted to be completely closed at any desiredpres sure. Thus the orifice at the top radiator would be adjusted to becompletely closed at .1" Hg differential in a building 217 feet highwhereas the bottom orifice would be adjusted to be completely closed at0 Hg differential.

Referring to the accompanying drawings:

Figure 1 is a view, in elevation,with parts broken away, of a heatingsystem for a tall building and suitable for practicing my improvedmethod.

Figure 2 is a view, in vertical section, of one form of radiator inletvalve which may be used, and of such construction as to be operatedresponsive to pressure differential at the inlet of the radiator.

Figure 2 is a fragmentary view of the valve of Fig. 2 modified to adaptit for use with a larger radiator.

Figure 3 is a similar view'of another form of radiator inlet Valve whichmay be used and of a construction operated by absolute pressure only;and

Figure 4, a similar view, with parts broken away, of a modification ofthe valve of Fig. 3 and desirable for use where low'pressure steam, orsteam delivered under partial vacuum, is supplied.

Referring to the system shown, this system is an example of a steamheating system for a tall building in which an appreciable altitude headis encountered as above referred to, the radiators shown, a plurality ofwhich are located on each floor of the building, being those which wouldbe provided on the two lower and the two upper floors of ar:tallbuildingnas 'abovesexplainemrthe mid section tofthe *radiator i'piping'assembl c'being omitted.-

In this :system a. boiler indicated :at :5 isirrepresented" as nflrediby anixelectri'callyf driven" oil burner 6': shown as providedwith anadjustable pressure-controlled: :electr'ic switchi device 6 in:-terposed in series with the-motor 6 of: the burner B in the electriccurrent lineawire's fi and fi the device 6 in accordance with commonpractice being adjustable to vary the steam pressure gen' erated intheboiler 5.

The boiler 5 connects by an upwardly extendingpipe I with. anoverhead'main le 'from which steam-'is supplied tothelidown-feedsrisers''l 'fcon' stituting parts of the main 1 and: opening into the latter atdifferent-points therealongas shown. Eachtriser l isi'showni asconnected by' pipes l with a vertical series of radiators 8 each ofwhich isprovi'ded with an inlet valve- 9 adjustable as hereinafter"explained to start to open-at-diifer ent pressures to:comp'ensa'te,as'aboveiexplaine'd, for'the altitude:head 'and for' the other purposehereinafter explained, and ea'ch of which opens progressively atdifferent rates toprovide'a particular relation, preferably a 1straight-line relation, between the pressure and the quantities of steamentering. the radiators.

The system is shown'for the supplyingof steam to radiatorsaplurality'ofwhich are located on each floor of a building, the radiatorsshown being those which would be provided on the two lower and the twoupper floors of a tall-building as'above explained;

Eachradi'ator 8- may be connected, as shown, at its outlet with athermostatic trap valve H! which functions 'to permit the outflow of airand condensate from the radiators, but closes automatically to preventthe escape of steam therefrom. The traps lfiopenintoreturn line pipes Hconnected: with pipes: l2 communicating with a downwardlyextending pipei3."

At the lower ends of the risers 1 are relatively large thermostatictraps I4* -connected with the return line pipes 12.

Preferably means'are provided for insuring the withdrawal ofairandcondensate from the radiators through the return line pipes ll, 12and I3 by the maintaining of a somewhat lower pressure in the returnline than'thepressure in the radiators or'the feed pipes'conn'ectedtherewith. In the system shown such a meansis employed comprising avacuum pump 15 driven-thy a motor is, the inlet of the pumpcommunicating with an upstanding pipe I! which opens into the upper endof a condensate tank :18 into which the return line pipe l3 discharges.The tank I8 at its'bottom communicates with a pipe i9 which opensinto'the-boiler 5' and through which the condensate is dischargedintothe boiler by a pump 20 interposed in the pipe l9 and driven by themotor l6.

As will be noted more in detail hereafter, the invention may bepracticed where the heating medium is supplied at either high or lowpressures, namely, in either a so-called pressure system or a vacuumsystem. If high pressure steam (that is, pressure above atmospheric) isused for supplying the radiators with steam, it may be desirable tomaintain a super-atmospheric pressure in .the return piping H-l3 insteadof exhausting the air fromthis piping, it being desirable that only asmall difierential pressure be maintained between the supply risers andthe radiators or return pipes.

Referring now to theiniet 'valves.--9"'for.i the 7 radiators;ands'whichmayzbex any one of aznum= ber of 'different forms as :forexample asl'illustrated'in Figs-1:2,.2d, 3 and'4, the formzshown inFi'gstZ and 2aiandwhi'ch. operates responsive to the difference betweenthe pressure in the radiator1andlthe pressure irr'thesupply line,comprises a casing 24 presenting-a chamber- 2 5 havingjan inlet 26connected with the pipe 1 and an outlet 21 connectedwith the inlet end'oi the radiator. Located in the chamber-15' and: in spaced relation tothe walls of the latter,"is a-flexible tubular metallic diaphragm 28preferably of the expansible bellows typ'e as shown; with'deeply'corrugated sidewalls, the lo'wer end-of the diaphragml 28 beingrig-idly 'c'lainpedin'place, to'provide a pressuretight joint, betweenaring 29- and a disk-30 1oc'ated in the "chamber 25 andrigidly clampedin place to provide a sealed joint between sections of the casing; thediski3ilbein'g-sapertured as by providingthereina series of openingsrepresented at3l toapermit oi the flow of the steam into thebellows-diaphragm. The upper end of the diaphragm 28I is closed byavalve plate 32'containing a central orifice 33 through which the steamsupplied to the valve-device Qpasses to theradiatorunder the control ofa valve located in the orifice 33 and represented at'34, the valve 34be-' ing of general coneshape and shown as mounted forlongitudinaladjustment relativeto'the orifice 33, as'byprovidingth'evalve "with a: depending stemlike 'portion 35 slidableinan opening inthe disk 30. -It is desired that the valve 34-be heldagainst"turningmovement and this is ef fected, intthe particular'construction'shown, by forming the" stemlike portion 35- ofnon-circular shape'in cross section, as by cutting away the op positesides of the lowerlcylindrical portion of the valve as- .shown,. an'd soshaping the opening 36 in: the "disk :30 as to prevent turning of thevalve.

The valve 34 is further provided with an up wardly' extending stemportion 31' secured to an externally threadedinut 38 which engages theinternal screw threads 39" of a valve stem 40: journalled: in ithecasing24 andheld against longitudinal movement; whereby'the valve 34 may beadjustedlongitudinally of'the orifice 33 by ro= tating the stem 40.

From the above it will bexunderstood that the underside of thep'latec32and the orifice '33 are subjected. tothe pressure of the steam supplyand the top'surface of the'plate" 32 to the pressure in the radiator,the bellows diaphragm 1'8 acting as a spring tending to i hold the:bellowscollapsed.

Thus assumi'ngathat'thervalvestem 40. has been adjusted to a positioniniwhich the plate .32 just contacts-at the wall of its orifice 33-withthe sides of-thecome 34; when the steam pressure at opposite sides ofthe plate32 is. equal, the raising of the steam pressure in the supplyline, or the reducing of: the pressurein the'radi'ator as bytheoperation: of; the. vacuum pump I5; eitherof which builds up pressurein the-bellows 28, causes the:plate.32 to rise relative'to the cone andthere by open the orifice 33proportionately to such movement-of theplate 32.

. Inthedesigning ofazsystem in. accordance with my. inventionxprovisionwould .be .made whereby the'openings'providedat the orificesfor thepassagevofn' steam to the: radiators; whenthe conevalves cooperatingtherewith occupy their extreme open positionsresponsive-to thesubjection thereof to thezmaximum'difierential pressure at which. it:isrdesignedthe:radiators operate at full capacity, would: be'of. suchefiectiveness as to supply the respective radiators with the requisiteamount of steam for the functioning of the radiators at their fullcapacity, it being understood that the larger the radiator the largerthe efiective orifice in the full open position of the valve. The valvecones, from which the orifice plates move but a slight distance only inresponse to slight increase of pressure differential, would be so shapedthat the amount of steam passing through the orifices is a substantiallystraight line function of pressure, rather than a hyperbolic function ofpressure as in the case of non-variable orifices.

In practice I would prefer to equip all of the radiators with plateshaving orifices of the same size and compensate for different sizes ofradiators by providing cones of different shapes, the larger radiatorshaving cones of greater taper. This is illustrated in Figs. 2 and 2awherein the valve of Fig. 2, provided for a radiator of approximatelyordinary size, but smaller than that for which the valve of Fig. 2a isprovided, would present less taper than the valve shown in Fig. 2a.

As will be understood, the valve 34 may be drawn up to set position inwhich the bellows 28 is under tension the degree of which determines thepressure at which the orifice initially opens, this being of advantageespecially where different temperatures are to be maintained indifferent rooms, and also to compensate for altitude head in theparticular heating system shown.

The valve as shown is provided on its stem 40 with stops 4| which extendinto the path of upward movement of the orifice plate 32 and which forma backing for this plate permitting the operator to lift the valve 34 bymanipulating the stem 40, into a position in which it presses upwardlyagainst the wall of the orifice 33 with such pressure as to cause thevalve to function as a stop valve preventing all flow of steam into theradiator.

The valve shown in Fig. 3 and which may be used at each radiator inplace of a valve of the construction in Fig. 2 and of a type operatingresponsive to absolute inlet pressure, as distinguished fromdifferential pressure, comprises a casing 42 divided in its lowerportion by an internal apertured web 43 into an inlet passage 44 leadingfrom an inlet port 45 and an outlet passage 46 leading to an outlet port41, the ports 45 and 41 being coupled in. any suitable manner with thepipe 1 and the radiator 8, respectively. Mounted in the orifice in theweb 43 is an orifice plate 48 containing the orifice 49 which'leads fromthe steam chamber represented at 50 to the outlet passage 46.

Located in the chamber 50 and in spaced relation to the walls of thelatter is a flexible tubular metallic diaphragm preferably of theexpansible bellows type, as shown, with deeply corrugated side walls,the upper end of the diaphragm which is open to the atmosphere asthrough a port 52 in the casing 42, being rigidly clamped in placebetween sections of the casing 42 to provide a sealed joint between thediaphragm and the sections of the casing. The lower movable end of thediaphragm 5| is provided with a valve 53 of general frusto-conical shapeand cooperating with the orifice 49 to control the amount of steampassing through the latter responsive to the degree of pressure of thesteam entering the chamber 44 through the inlet 45.

The valve also comprises a stem 54 rotatable, but held againstlongitudinal movement, in the casing 42, the lower end of the stem 54being externally threaded as represented at 55 at which it is screwedinto the internal threads 56 provided in an upwardly opening socket 51in a nut 58 held against rotation by a pin 59 secured in, and dependingfrom, the top of the casing 42 and slidable in an opening 60 in a flange6| on the nut, the nut 58 being thus movable up and. down by rotation ofthe stem 54 in the appropriate direction. Interposed between the nut 58and the lower end of the diaphragm 5i is a compression spring 62.

As will be understood, the valve 53 is caused to open and permit steamto enter the radiator responsive to the flow of steam into the chamber44 at a pressure depending upon the resistance of the valve 53 to upwardmovement and which resistance is controllable by varying the tension ofthe spring 62 all to the same end as explained above in connection withthe construction shown in Fig. 2, it being possible to entirely closethe valve against opening, by forcibly pressing the valve 53 against thevalve seat 48.

When high pressure steam, that is, steam at any pressure aboveatmospheric, is used in the heating system, the spring 62 will be acompression spring so as to aid the atmospheric pressure within thediaphragm and the expansive force of the diaphragm itself in maintaininga balance against the higher steam pressure exerted on the outside ofthe diaphragm. When low pressure steam, or steam delivered under apartial vacuum, is used in the system the spring 62 maybe a tensionspring to maintain the proper balance between the forces exerted on thetwo sides of the diaphragm 5i or, as shown in the modification asillustrated in Fig. 4, a compression spring 63 may be added Within thesteam-chamber 44 and positioned to press upwardly against the lower endof the flexible diaphragm 5|, the spring 62 in such structure being acompression spring, and thus assist the low pressure steam in balancingthe higher atmospheric pressure within the diaphragm.

While I have illustrated and described certain particular constructionsconstituting embodiments of my invention and have illustrated certainparticular forms of apparatus for practicing my novel method, I do notwish to be understood as intending to limit it thereto as theconstructions shown may be variously modified and altered and the methodpracticed by other constructions of apparatus without departing from thespirit of my invention, and in this connection it may be stated that myinvention, as to certain phases thereof, is not limited to a system fora tall building as explained, but may be used in a system of such lowheight, either wherein all of the radiators are on one floor or on aplurality of superposed floors, that no appreciable altitude head isencountered in using the system.

What I claim as new, and desire to secure by Letters Patent, is:

l. The method of supplying steam to a plus rality of radiators connectedby a system of supply piping to a source of steam supply which consistsin increasing the freedom of flow of steam from the supply piping to theradiators as the diflferential between the pressure in the piping andthe pressure in the radiators increases, and decreasing the freedom offlow of steam from the supply piping to the radiators as thedifferential between the pressure in the piping and the pressure in theradiators decreases, and so controlling the said changes in freedom offlow of steam as to cause the amount of steam passing into the radiatorsto constitute a substantially straight line function of the saiddifferential.

2. The method of supplying steam to a plurality of radiators connectedby a system of supply piping to a source of steam supply and disposed atsuch relative altitudes that an appreciable al-' titude head exists,which consists in increasing the freedom of flow of steam from thesupply piping to the radiators as the differential between the pressurein the piping and the pressure in the radiators increases, anddecreasing the freedom of flow of steam from the supply piping to theradiators as the differential between the pressure in the piping and thepressure in the radiators decreases to the end of causing the amount ofsteam passing into the radiators to constitute a substantially straightline function of the said differential, and reducing the freedom of flowto the radiators at the higher altitude as compared to the freedom offlow to the radiators at the lower altitudes by quantities which aresuiiicient to compensate for the effect of the altitude head to the endof causing the same relative quantities of steam to be supplied'to theradiators at the higher altitudes as to the radiators at the loweraltitudes.

3. In a steam heating system, the combination of a source of steam, aplurality of radiators, a system of piping adapted to conduct the steamto the radiators, said radiators being disposed at such relativealtitudes that an appreciable altitude head is produced in the system ofpiping, re-

rality of radiators of different sizes through re stricted openings ofchangeable size, which method comprises: a varying the differential ofpressure between the radiators and thesource of steam supply; causingthe effective area of the openings to increase as the differentialincreases; and causing the rate of increase to be greater proportionallyas the size of the radiators is greater.

5. The method of supplying steam to a plurality of radiators ofdifferent sizes through restricted openings of changeable size, whichmethod'comprises: varying the difierential of pres sure between theradiators and the source of steam supply; causing said openingsto beclosed 6. The method of supplying steam to a plurality of radiators ofdifferent sizes through restricted openings of changeable size, whichmethod comprises: varying the difierential of pressure between theradiators and the source of steam supply in accordance with temperaturerequirements; causing the effective area of the openings toautomatically increase and decrease respectively as the diiferentialincreases and decreases; and causing the rate of variation in effectivearea of the openings at the respective radiators to be greater or lessproportionally as the size of the radiators is larger or smaller.

FRED I. RAYMOND.

